Recently, we have been impressed by the research potential of the Chinese hamster. Gingival and cheek pouch tissue biopsies were taken from normal control animals and matched diabetic animals. Electron microscopic examination of the basement membrane of small blood vessels revealed a marked thickening of the membrane in the diabetic animals. It appears that gingival or oral mucosal biopsies could replace the more difficult and painful muscle biopsies as a diagnostic tool in both the diabetic and the prediabetic patient. Permeability changes in the diabetic animals being studied utilizing horseradish peroxidase as a marker. Examination of the soleus muscle as well as the tongue skeletal muscle has revealed lipid and glycogen droplets witin the mitochondria of the diabetic animals. These accumulations may be the result of an altered metabolism. Further, morphometric, histologic and biochemical studies will be instituted. The effects of hypophysectomy and growth hormone on the development of the vascular lesion is also been investigated.